Fuel Injector Tuning: Performance & Optimization

Hello everyone,

I've been reading quite a bit about "larger" injectors recently and I'm curious. I have a 1Z model from 03/94 that doesn't run as smoothly as it used to. Furthermore, it's affected by the well-known needle lift valve issue.

There are now several price ranges mentioned... I've read almost everything, ranging from 180 to 1000 euros... it's likely that sometimes the prices refer only to the nozzles, while other times they include complete "sets" with brackets and other small parts.

Due to cost considerations, I have always refrained from replacing the needle lift sensor, as I can tolerate the severe jolting that occurs every 300-500 km (I hope the engine can handle it too).

However, it seems possible to extract a bit more power from the 66kW engine by using different nozzles, so if that's even a possibility, I would also replace the NHG (presumably a component).

- Can you install "larger" injectors in the 1Z engine without needing to tune the chip?
- What are the minimum costs to expect, and what is the cost of a complete replacement with a new heat generator (NHG)?

What are your general thoughts on the idea? The comments I've read so far mostly refer to the other engines (A...).

Hello Tino,

For your 1Z engine, the slightly larger injectors from the AFN engine (110 hp) would be a suitable option.
However, based on my own experience, I would recommend, if possible, to first test these nozzles (e.g., used ones) and then decide whether to use them.
The opinions regarding the properties seem to vary from person to person. In any case, I wasn't satisfied and reinstalled my original nozzles.

Best regards,
Albrecht.